Difference between P and PJ?

I've been missing that Precision thump these days, so I'm ordering a body with a Precision rout from Warmoth. I've been thinking maybe I'll add a bridge pup just for versatility, but I was wondering--

I remember having a Fender PJ and a P, and I recall thinking that the PJ with the neck pup soloed just didn't sound as meaty as my Precision. Was that just the nature of the two beasts, my imagination, or is there something in the wiring that explains this?

I think some P/J setups have odd volume characterisics because of the interaction between the single coil J pickup and the humbucking P pickup. I tried a Hot Rod P-bass once, and found the volume dropped a little with both pickups on full, for example. I spoke to a seemingly very knowledgeable player about this, who told me the single/humbucker interaction was the issue. This could be avoided with a humbucking J pickup, like Lindy Fralin's P/J set which includes a Split Jazz linear humbucker.

electronically, they have seperate volume pots, but common tone, right?

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Yes. I didn't open it up, but that's how they respond to the three knobs. So, if wired that way and the j pup turned all the way down, theoretically there should be no reason for it to sound different than a P bass with no J bridge pup, right?

I know that some people insist on using a 3 way switch instead of the V-V-T setup, so you're not alone in detecting some sound difference. If I remember it correctly, unless you use the 3 way switch, you'll never be able to solo the P pickup by _completely_ canceling out the effect the J pickup has on the way the electronics interact with the strings. I've always wondered if it was really that big of a deal.

Yes. I didn't open it up, but that's how they respond to the three knobs. So, if wired that way and the j pup turned all the way down, theoretically there should be no reason for it to sound different than a P bass with no J bridge pup, right?

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Either that, or you could use a couple stacked pots, and have it like :

Yep. It happens. My BCR has a pup selector switch and the P definitely sounds beefier when solo'ed with the switch, compared to using the volume controls.

I think the "humbucker vs. single coil interaction" argument is pure BS. What it is, is just pickup loading. Happens on any passive bass or guitar with more than 1 pickup.

Not for nothin, but this thread should probably be on the pickup forum...

Here's an article that came from someplace on the guitarnuts.com website. I just went looking to try to find the link, but they completely changed the site and turned it into an ad generator.

Does the sound fatten up even if you only back either volume control off just a little bit, like by 10% or so? If so, this is normal for vintage Gibsons. With both volume controls at maximum the two pickups are wired directly in parallel and each applies a fairly high load to the other. As soon as you back either volume control off even just a little you throw 100k or so of resistance between the two pickups which isolates them so they no longer load each other. The 100k of resistance isn't that significant to the high impedance amp, so you get almost full volume from both pickups and the sound is fat.

A "cure" for this is to put a 47k resistor between each volume pot and the pickup switch. This amount of resistance will barely reduce your volume at all, but there will always be at least 94k of resistance between the two pickups, preventing them from loading each other.

Not all vintage gibsons do this because often the cheap pots they used didn't go all the way to the end of their electrical travel anyway, leaving a little resistance between the pickups even at full volume.

I'm glad you brought this up, I need to make mention of this "fix" on the website because I've not seen anyone else note it.

Finally, I should add that a similar dynamic is at work in Fender style guitars. When you select the neck and middle pickups together, each is loading the other, likewise when you choose the mid and bridge pickups together (or the neck and bridge on a Tele style guitar). That is why the signal usually gets a little quieter, instead of louder, when you select the combination positions on the selector switch. If you want a different sound from your Strat or Tele try putting about a 20k resistor between the hot lead of each pickup and the selector switch. You'll sacrifice a bit of overall volume (not very noticeable at all if you're feeding a hi impedance amp or effect) but will get a fatter sound in the mixed positions.

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I've tried this and it works. 3 of my basses now have this mod. This will also "fix" a passive blend pot so the pan is smooth and the center position actually sounds like the center.

The value will depend on the pickups and the pots in each bass. Start with a 22k on each hot. If you need more you can increase it to 47k. And it's ok to use different values, if you tend to favor one pickup (and never solo the other) put the heavier resistor on the other one.

Thanks folks for the informative responses. It looks like I have some things to think about and possibly some wiring options to explore. I think I'll get the PJ set up and test it to figure out if I need a switch.

Oh, and maybe Mitch is right about this being in the Pickup forum. If a mod sees fit to move it, please do. Thanks.

Thanks folks for the informative responses. It looks like I have some things to think about and possibly some wiring options to explore. I think I'll get the PJ set up and test it to figure out if I need a switch.

Oh, and maybe Mitch is right about this being in the Pickup forum. If a mod sees fit to move it, please do. Thanks.

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I set up almost all of my basses in PJ fashion. I find myself usually using just the P pup, because that's what I like. Iv'e always used a Fender P bass until the past year or so. But' i do love to have the versatility for when I want it and I also like the way that the J pup gives the body some aestetic balance.
Depending on the bass, what the woods are, what the neck is, electronics etc., I can get just as much thump or more, depending which bass I use. some more, some less.
Point being, you had the answer yourself, I believe, in your first post. Every bass is going to be different.

Hm, the J-Bass pup won't kill the P tone at all, however it was probably that the pup in the bass wasn't as nice as yoiur other P. P-J is a good combo, and control wise, go with BLEND - VOLUME - TONE. Don't do stacked pots, harder to make quick changes.

One of the best PJ sounds I got was using a P-pickup with a Tele-style pickup in the bridge.
A pickup from a 1968 tele-bass.
This pickup blended much better, with a p-pickup than a J-pickup.
No lose of volume, more grit.

this may have happened for a variety of reasons first of all you should know that on the PJ fenders the P pickup is placed elsewhere(closer to the neck than on a standard P-bass)due to the fact the designers had in mind a combination of P- and J- bass(on the Jazzbasses the attitude mostly comes from the bridge pickup)Other than that the answer could much simpler,that the pickup on the p-bass is hotter(and probably a different model)And also remember the wood factor i wouldn't be suprised if the p-bass has an ash body and thus sounds fatter(I'm pretty sure the pj-basses from fender come only with alder bodies)